Scrambling Information

The purpose of this page is to inform the user of the different types of scrambling systems, and where
they are being used in the Lane County, Oregon area. The only intent is to familiarize the serious
scanner listener with the different types of sounds emanating through their radios and who uses them.
Please do not ask for any information that would assist in defeating these systems. I will not provide
any nor do I know of any. Sample sounds below are slightly modified from their original recordings.

Phase Inversion

Simple analog encryption system where the high frequencies are inverted low and the low freqs are
inverted high. A hinge point of about 3,300Hz is typically used. Everything above the hinge point
becomes low, everything below becomes high. This type of encryption system has the characteristics
of 'am' sideband, or 'Donald Duck' if you will.
Users Include:

Florence PoliceJunction City Policesome local taxi companiessome local towing companies

Rolling Phase Inversion

A variation on normal phase inversion, the rolling version uses a variable hingepoint that cycles through
different points as the conversation progresses. Depending on the level of security, more or less hinge
points can be used. Typically you'll hear a 1200 baud databurst at the beginning of the transmission
followed by tinny sound.
Users Include:

Eugene Police, detectives only (note: EPD seems to have abandoned using the scramblers)

Digital Transmission

The newest scrambling (type) system to be heard in the Lane County area. To the average scanner
user with an analog scanner, the digital mode pretty much restricts listening. This sounds much
different than the DVP version listed below. This is not technically scrambling, as the signal
itself is not encrypted, but achieves the same effect due to the lack of digital scanners.
Expect to hear computer type data bursts, similar to packet radio.

Notice the NEW digital sound. It is clearly different from the original mode.
Since this new mode has been in place, Springfield has NOT been in analog.
Something must be working right, finally.

Users Include:

Springfield Police (full time)

DVP - Digital Voice Privacytm - Motorola

This form of encryption comes in two flavors; commercial and military. The only difference is that the
commercial version doesn't use as many keys to encrypt the signal as the military version does. The
keys can be changed as often as the user likes. Federal agencies actually have radios that can be
rekeyed right over the air versus having to use a keyloader which plugs into the radio. This type of
system is distinguished by the squelch type sound followed by a high pitched ring at the end of
transmission. You can achieve almost the same type sound by turning your squelch all the way down.
Users Include: